1. Field of the Invention
The present invention relates to an information record medium such as an optical disk of a high recording density type, which is capable of recording information such as video information, audio information and the like at a high density, and which is represented by a DVD (Digital Video or Versatile Disk). The present invention also relates to a recording apparatus for recording the information onto the information record medium, and a reproducing apparatus for reproducing the information from the information record medium.
2. Description of the Related Art
Conventionally, a so-called LD (Laser Disk) and a so-called CD (Compact Disk) are generalized as optical disks, on which information such as video information, audio information and the like is recorded.
On the LD or the like, the video information and the audio information are recorded together with time information indicating a time at which each information is to be reproduced with respect to a reproduction start position, which each LD or the like has, as a standard position. Thus, other than a general normal reproduction to reproduce the recorded information in the order of recording, various special reproductions are possible, such as a reproduction to extract and listen to an only desirable music out of a plurality of recorded music, a reproduction to listen to the recorded music in a random order and so on, in case of the CD, for example.
However, there is a problem that, according to the above mentioned LD or the like, a so-called interactive and variegated reproduction is not possible in which the audience can have a plurality of selection branches as for the video or audio information to be displayed or sound-outputted and in which the audience can select them to watch or listen to it.
Namely, it is impossible for a user to choose the language used in the subtitle displayed on the screen (e.g., from subtitles of Japanese and the original language) in the case of watching a foreign movie recorded on a LD or to choose the voices of a song (e.g., from English voices or Japanese Voices) in the case of listening to the music recorded on a CD.
Nowadays, apart from the above-mentioned conventional CD, it has been proposed and developed a DVD which is an optical disc which disc size is identical to CD and which recording capacity is enhanced to be approximately ten times larger than that of CD. By recording the subtitles and/or voices of plural languages on the DVD, the user can arbitrarily choose them and enjoy the various and interactive reproduction.
However, in order to record, on the DVD, the voices of plural kinds of languages and/or various kinds of music, the capacity of those information to be recorded necessarily becomes quite large and hence those information should be recorded on DVD in an appropriate efficient recording format, otherwise the processing for retrieving audio information, etc. to be reproduced is complicated and troublesome at the time of reproduction and the reproduced voices or music may be broken or interrupted in its reproduction due to the long retrieving time of the audio information. This results in a serious problem in the reproduction.